Optimizing the Thermal Conductivity of 2D Materials/Copper Composites through Strain-Controlled Electron-Phonon Coupling Effect

In recent years, 5G mobile communication technology, high-power devices, and micro-integrated electronic devices have developed and iterated rapidly. However, the heat generation of the devices cannot be ignored under such high-power consumption, which affects their normal operation and decreases the lifetime, or even causes damage in severe cases. Copper is the most widely used heat conducting material in electronic devices, but further improvement of its thermal properties to match the demand is still a crucial challenge. Graphene with ultra-high theoretical thermal conductivity is an ideal material to be combined with copper to improve its thermal conductivity, but the introduced graphene/copper interfaces bring phonon/electron scattering, which limits the heat transfer. In this work, laminated graphene-copper composites (HP-GCCs) are prepared by a hot-pressing strategy, the graphene/copper interfaces can form a stress-induced phonon-electron coupling effect through controlling the graphene distribution, which can improve the phonon-electron transmission of the interfaces and thus improve its thermal conductivity. The HP-GCCs exhibit a high thermal conductivity of 440.60 W m⁻¹·K⁻¹, showing reduced temperature-rise and improved efficiency when applied to devices in the practical applications. The investigations of the optimized graphene distribution of the composites through analyzing the mechanism of interfacial heat conduction provide valuable guidance for optimizing the synthesis and properties of 2D materials/copper composites.